Blueberry production is currently of great interest as a result of the known health benefits of the fruit. Highbush blueberry hectarage has been increasing steadily, with the 2010 hectarage totaling 9100, 46,300, and 77,300 ha in Canada, North America, and worldwide, respectively (Brazelton, 2011). The increase in planted highbush blueberry hectarage requires healthy nursery stock, some of which is produced in containers. In addition to potted nursery stock for commercial field production, potted blueberry plants are also in demand by consumers for home gardens. Recent interest in urban agriculture and the local food movement has increased consumer appeal for growing edible crops, especially using organic methods; however, blueberry production is challenging because of specific soil pH requirements [i.e., pH 4.2–5.5 (Puls, 1999)]. For home gardeners, in-ground cultivation of blueberry plants is often not possible given these soil requirements; therefore, containerized blueberry production is a promising alternative for home gardeners to reap the health benefits of blueberry fruit grown in their own backyard.
Despite the detailed recommendations available for field production of blueberries and the need for similar recommendations for container production, very few scientific studies have been conducted on the production of northern highbush blueberry plants in containers (Heiberg and Lunde, 2006; Miller et al., 2006; Smolarz, 1985). In addition, limited research has been conducted on the response of northern highbush blueberry plants to organic growing substrates and fertilizers (Miller et al., 2006; Strik et al., 2017). Some successful growing substrates for potted blueberries have included such components as coir, perlite, turf, peat, bark, wood fiber, sphagnum moss, and sand (Heiberg and Lunde, 2006; Hortidaily, 2015; Kingston et al., 2017; Miller et al., 2006; Smolarz, 1985); however, an industry-standard growing substrate for containerized blueberry production has not been identified. An appropriate growing substrate for containerized blueberry production must ensure appropriate physical properties and drainage because of the susceptibility of fine blueberry roots to root rot in poorly drained soils (de Silva et al., 1999). Physical properties for a typical nursery growing substrate include a total porosity of 50% to 85% (Agriculture and Agri-Food Canada, 2003), with appropriate levels for potted blueberries at the high end of this range [e.g., 76% to 86% (Kingston et al., 2017)]. In addition, appropriate chemical properties of the growing substrate need to be maintained during containerized blueberry production, including pH (4.2–5.5), EC (<2.0 mS·cm–1), and nutrient concentrations (Kingston et al., 2017; Machado et al., 2014; Puls, 1999; Retamales and Hancock, 2012). Despite the great influence of fertilization strategies on the root-zone environment, limited research has evaluated nutrient management strategies using conventional and organic fertilizers for containerized northern highbush blueberry production (Miller et al., 2006; Smolarz, 1985). Therefore, further research is needed to develop nutrient management strategies for potted blueberry plant production in commercial nurseries and also for home gardeners to grow and maintain healthy, high-yielding potted blueberry plants.
In addition, current nursery production of blueberry plants is most commonly in a #1 or #2 nursery container size, using conventional growing substrates and fertilizers. However, to reach additional markets, especially consumers favoring long-term organic container production of blueberries, nursery production practices can be adapted to supply a complimentary product. To ensure low-maintenance solutions for consumers, finishing nursery-grown blueberry plants in a larger container (i.e., #5 vs. #1 or #2), in combination with organic production, will eliminate the inconvenience of repotting for consumers, at least for the first year. This large, organically grown blueberry plant has the potential to be a value-added product for nursery growers. Therefore, this study aimed to develop fertilization methods for organic and conventional #5 potted northern highbush blueberry plants. Specifically, the objective of this study was to determine the optimal fertilization rates for each of following three methods for #5 potted Vaccinium corymbosum ‘Duke’ production: organic substrate with organic granular (OG) fertilizer, organic substrate with organic liquid (OL) fertilizer, and conventional substrate with controlled-release conventional (C) fertilizer.
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Strik, B., Vance, A.J. & Finn, C.E. 2017 Northern highbush blueberry cultivars differed in yield and fruit quality in two organic production systems from planting to maturity HortScience 56 844 851
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